Team,

We have a requirement to have the same channel name in two different qmgrs hosted on CP4I/OCP. From the setup, we understand that each channel should have a corresponding route created in OCP. Unfortunately when we are creating a custom route of these channels we are getting "HostAlreadyClaimed" error and the route is rejected even though they are in different namespaces/projects on OCP.

Is there any way we can overcome this limitation? Any advice is appreciated. 


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Dilip Veeturi
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Allowing for both qmgrs pods to run on the same worker node, you should at least include the MQ qmgr port assignment (at the node level) into your custom route.
On the other hand if you are looking at some kind of failover, you should make a rule that prevents the MQ pods from being deployed to the same worker node....

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Francois Brandelik
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When you use a Route, you are creating some configuration for the HAProxy component in OpenShift Container Platform (OCP).  HAProxy routes network traffic based on the contents of the "Server Name Indication" (SNI) header used as part of TLS.  You need a unique value in the SNI header, so that HAProxy can route to the correct queue manager instance.  As described in Configuring a Route to connect to a queue manager from outside a Red Hat OpenShift cluster, older versions of MQ put the MQ channel name in the SNI header - this means that you have to set up the Route to use the channel name for routing, which forces the channel name to be unique in the OCP cluster.  From MQ 9.2.1 onwards, there is a new option to configure MQ to put a host name in the SNI header, which would allow the re-use of channel names.

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Arthur Barr
Container Architect, IBM MQ
IBM
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Thanks, Arthur for your response. Unfortunately, we are using CP4I 2020.4 which has only support to 9.2.0.x. Is there any alternative approach?

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Dilip Veeturi
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Original Message:
Sent: Mon November 29, 2021 05:29 AM
From: Arthur Barr
Subject: Same channel name in two different queue managers - CP4I/OCP

When you use a Route, you are creating some configuration for the HAProxy component in OpenShift Container Platform (OCP).  HAProxy routes network traffic based on the contents of the "Server Name Indication" (SNI) header used as part of TLS.  You need a unique value in the SNI header, so that HAProxy can route to the correct queue manager instance.  As described in Configuring a Route to connect to a queue manager from outside a Red Hat OpenShift cluster, older versions of MQ put the MQ channel name in the SNI header - this means that you have to set up the Route to use the channel name for routing, which forces the channel name to be unique in the OCP cluster.  From MQ 9.2.1 onwards, there is a new option to configure MQ to put a host name in the SNI header, which would allow the re-use of channel names.

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Arthur Barr
Container Architect, IBM MQ
IBM
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